Vacuum relay

ABSTRACT

An improved construction for a miniature vacuum relay is provided, whereby the relay is capable of a latching operation. The relay responds to an electric pulse of a first polarity to move from one electrical switching condition to another, and it remains in the second electrical switching position until a second pulse of opposite polarity is applied to the relay, at which time the relay returns to its original switching position. A permanent magnet is included in the magnetic circuit of the relay so that when the armature is moved against the action of the biasing spring of the relay to a particular position, it is retained in that position by the permanent magnet until an opposing magnetic flux is created in the magnetic circuit to nullify the action of the permanent magnet.

United States Patent [72] inventor Victor E. De Lucie Los Angeles, Calif. [21] Appl. No. 34,387 [22] Filed May 4, 1970 [45] Patented Dec. 21,1971 [73] Assignee Torr Laboratories, Inc.

Los Angeles, Calif.

[54] VACUUM RELAY 7 Claims, 3 Drawing Figs.

[52] U.S. Cl 335/170, 335/230 [5 [1 Int. Cl "01h 9/20 [50] Field oISearch 335/l70, 179,166 BH, 166 J, 229, 230, 79, I96, 151

[56] References Cited UNITED STATES PATENTS 3,470,510 9/1969 Richert 335/230 3,4ll,ll8 ll/1968 Fellows etal. 335/151 Primary Examiner- Harold Broome Attorney.|essup & Beecher ABSTRACT: An improved construction for a miniature vacuum relay is provided, whereby the relay is capable of a latching operation. The relay responds to an electric pulse of a first polarity to move from one electrical switching condition to another, and it remains in the second electrical switching position until a second pulse of opposite polarity is applied to the relay, at which time the relay returns to its original switching position. A permanent magnet is included in the magnetic circuit of the relay so that when the armature is moved against the action of the biasing spring of the relay to a particular position, it is retained in that position by the permanent magnet until an opposing magnetic flux is created in the magnetic circuit to nullify the action of the permanent magnet.

VACUUM RELAY A further feature of the relay to be described is the establishment of a connection from a terminal post to the movable contact within the evacuated envelope by means of a resilient spring member which is attached to both the terminal post and to the movable contact, and which establishes a positive connection between the terminal post and the movable contact, and yet permits the movable contact to be moved freely with the armature to make and break selectively with the fixed contacts of the relay.

BACKGROUND OF THE INVENTION The vacuum relay to be described herein includes a movable armature and magnetic pole pieces enclosed within an evacuated glass or ceramic envelope. The energizing coil for the relay, and the major 'part of its magnetic circuit, are mounted externally of the envelope. This construction is advantageous in that the relay responds with high sensitivity to the energization of its coil, since the magnetic circuit projects directly into the evacuated envelope. In a practice of the invention, a permanent magnet is included in the portion of the magnetic circuit which is outside of the envelope, and this permanent magnet performs a latching function, in that the armature within the vacuum envelope is held in a particular position by the permanent magnet, so that continuous energizing of the relay coil is not necessary.

The vacuum relay to be described is of the general type which comprises an evacuated chamber formed by the aforesaid glass envelope, and which is closed at one end by a metallic end wall. The magnetizable core of the relay extends through the metallic end wall, and it is used to draw a pivotally mounted magnetic armature in towards the end of the core, and against the force of a biasing spring. The armature is pivotally mounted within the evacuated chamber on the inner face of the end wall, and the spring tends to bias it away from v the end wall.

In the construction of the relay to be described, an insulating post composed, for example, of sapphire is staked to the pivotally mounted armature, and the movable contact is formed by a conductive collar attached to the upper end of the post. The collar is composed, for example, of molybdenum, tungsten or other suitable refractory material. The fixed contacts of the relay to be described are in the form of conductive posts which extend through the glass envelope of the relay and into the evacuated interior chamber thereof.

In the single-pole double-throw construction of the relay, the fixed contact posts are positioned and shaped so that their ends extend across the path of the movable contact, for example, in front of and behind the movable contact, so as to be selectively contacted thereby as the armature is moved angularly between its two pivotal positions. The fixed contact posts are also preferably formed of a suitable refractory material, such as tungsten or molybdenum, for long operational life.

In carrying out the concepts of the invention, in one of the aspects thereof, a resilient connection is made to the movable contact from a further electrically conductive post extending through the glass envelope. The resilient connection is in the form of a U-shaped resilient spring strip which is attached to the further post, and which is also attached to the insulated movable contact post. The strip is electrically conductive, and it is electrically connected to both the movable contact and to the further post. The U-shaped resilient strip elongates and contracts as the movable contact moves with the armature, and it provides a positive electrical connection between the further post and the movable contact. The further post, as well as the movable contact post may be coated with silver-plated copper. The U-shaped resilient strip may be formed, for example, of beryllium copper and it may also be silver plated. The ends of the U-shaped strip may then be wrapped around the aforesaid posts, and the strip becomes welded to the posts within the chamber of the relay by the known phenomenon of atomic diffusion, as the chamber is evacuated.

The construction described in the preceding paragraph is advantageous in that there are no sliding contacts developed in establishing appropriate electrical connection to the moving contact within the relay. This precludes any tendency for arcing and fouling of the movable contact connection within the evacuated relay envelope. The relay assembly is easy to construct, in that the fixed contacts and the U-shaped resilient strip may be mounted in the envelope as a first subassembly, and the other components may be mounted on the end wall as a second subassembly. The two subassemblies may be brought together and subsequently joined by a simple heliarc operation. The aforesaid welding of the resilient strip to the movable contact post is achieved automatically during the subsequent evacuation of the envelope, and due to the aforesaid atomic diffusion phenomenon.

The miniature vacuum relay to be described herein is particularly suited for high voltage applications, and it does not exhibit any tendency for deterioration when used with high voltages and peak currents, even under high ambient temperature conditions. The inclusion of a permanent magnet in the external magnetic circuit of the relay permits a latching operation, as described above, so that continuous currents are not required in order to maintain the relay in any of its switching states, and the relay responds simply to electrical pulses of opposite polarity to be switched from one state to another. Also, and as described briefly above, the construction of the movable contact assembly provides an improved electrical connection to the movable contact without the creation of deteriorating arcing conditions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side section of a relay constructed in accordance with the concepts of the present invention;

FIG. 2 is a cross-sectional view taken along the line 22 of FIG. 1; and

FIG. 3 is a sectional view of the armature subassembly of the relay of FIG. 1.

DETAILED DESCRIPTION or THE ILLUSTRATED EMBODIMENT As illustrated in the drawing, the miniature vacuum relay of the present invention comprises an evacuated envelope 10. The envelope may be formed of glass, or other appropriate vitreous material. The envelope is closed at its lower end by an end wall which includes an annular member 11 formed of a ferrous, or other magnetizable material.

An apertured disclike member 12 is attached to the inner surface of the annular member 11, and a disclike core member 13 is attached to the inner surface of the member 12 and extends through the member 12. The core member 13 is formed of iron, or other appropriate magnetizable material, whereas the member 12 is formed of a nonmagnetic material, such as Monel metal. The members ll, 12 and 13 together constitute the end wall for the envelope 10, and together with the envelope define the inner chamber which is evacuated, and in which the moving components of the relay are situated.

An armature 14 composed of ferrous, or other magnetizable material, is pivotally mounted within the chamber on the annular member 11 for movement towards and away from the inner end of the core member 13. The armature 14 is so mounted by means of a pin 14a which, in turn, is supported on a pedestal 11a of ferrous, or other suitable magnetizable material, the pedestal 1 1a being welded, or otherwise attached to the inner surface of the annular member 11.

An electric coil 16 is mounted externally of the envelope 10, and it surrounds a permanent magnet 17. The permanent magnet 17 may have a circular cross section, with a diameter corresponding to the diameter of the core 13. As shown, the permanent magnet 17 may be mounted in axial alignment with the core 13. The permanent magnet 17 may be longitudinally magnetized with a north pole at one end and a south pole at the other end. The annular member 11 is actually integral with a cylindrical housing 11b for the coil 16, as shown, and it forms an upper flanged edge for the housing. The coil 16 is supported in position around the permanent magnet 17 within the housing 11b by means, for example, of a cover 18, the cover being held in place by a nut 19 which is threaded to a stud 20 protruding from the lower end of the assembly. The

cover 18 may also be formed of magnetizable material, and completes the magnetic circuit for the assembly. Electrical terminals 21 may be provided on the cover for the coil 16. The assembly may be evacuated in accordance with known techniques by a passageway extending through the center of the permanent magnet 17 and core 13 and into the interior of the envelope 10.

A spring 22 normally biases the armature 14 to the tilted condition shown in FIG. 1. However, when the coil 16 is energized by a pulse of a first polarity, the armature 14 is drawn down against the upper end of the core 13, and under the influence of the permanent magnet 17. The armature is held in that position by the action of the permanent magnet 17, until a pulse of opposite polarity is applied to the terminals 21, so asto counteract the magnetic field of the permanent magnet, and permit the spring 22 to return the armature 14 to its illustrated tilted position Therefore, the relay of FIG. 1 has a latching characteristic, and may be actuated from one switching position to the other by pulsesof opposite polarity, and the relay does not require continuous current in the coil 16 to hold it in any particular switching position.

An insulating post 24 (FIG. 3) formed, for example, of sapphire is staked to the armature l4, and the post extends outwardly from the plane of the armature. The post is surrounded, for example, by an electrically conductive sleeve 26, the sleeve being formed of beryllium copper, or other electrically conductive material, and silver plated for the reasons explained above. The movable contact of the relay is in the form of a collar 28 which is fitted over the end of the sleeve 26, as best shown in FIG. 3. The collar 28 is electrically connected to the sleeve 26, so that both the collar and the sleeve may be considered components of the movable contact assembly. The collar is formed preferably of an electrically conductive material having high refractory characteristics, such as molybdenum or tungsten, so as to be capable of breaking relatively high currents without deterioration.

The fixed contacts of the relay are formed, for example, by a pair of electrically conductive posts 30 and 32 formed of tungsten or other electrically conductive material of high refractory characteristics. The posts 30 and 32 extend through the envelope 10 through the interior, and the lower ends of the posts are bent over to extend across the path of the movable contact collar 28 in front and behind the movable contact. The posts 30 and 32 are positioned so that the post 30, for example, is contacted by the movable contact 28 when the armature 14 is in the tilted position shown in FIG. 1, and so that the post 30 is engaged by the movable contact 28 when the annature 14 is moved down against the end of the core 13.

Connection is established to the movable contact 28 by means of a further electrically conductive post 36 which extends through the top of the envelope 10. A resilient electrically conductive strip 38 is affixed to the lower end of the post 36, and to the collar 26 of the post 24. The strip 38 has a U- shaped configuration as best shown in FIG. 2. The strip 38 is composed, for example, of heat-treated beryllium copper, and it is silver plated, so as to achieve the desired welding action with the post 36 and with the collar 26 of the post 24, when the chamber of the relay is evacuated. In this way, a positive electrical connection is established from the post 36 through the resilient strip 38 and through the sleeve 26 to the movable contact 28. This positive and continuous contact is maintained without any tendency for interruption as the movable contact assembly moves back and forth along its path.

The invention provides, therefore, an improved vacuum relay which is constructed to achieve a latching action, as described above, and which may be operated satisfactorily over long periods of time, even in con'unction with extremely high voltages and peak currents, an even under high temperature ambient conditions, all without any appreciable deterioration in the electrical circuit of the relay.

It will be appreciated that although a particular embodiment of the relay of the invention has been shown and described, modifications may be made. It is intended in the following claims to cover all the modifications which come within the scope of the invention.

What is claimed is:

1. An electric switching device including: an envelope; a magnetic member forming an end wall for said envelope and having an opening therein; a movable magnetic armature mounted in said envelope and extending across said opening and movable toward and away from said magnetic member; resilient means in said envelope for biasing said armature to a first position displaced away from said magnetic member; a magnetic core member positioned in said opening in said magnetic member; a permanent magnet mounted adjacent said magnetic core member in axial alignment therewith on the opposite side thereof from said armature; and energizing means mounted adjacent said magnetic member and surrounding said magnetic core member for creating a magnetic field in said core member to draw said armature toward said magnetic core member and into the magnetic field of said permanent magnet to a second position so as to cause said armature to latch magnetically in said second position.

2. The electric switching device defined in claim 1, in which said armature is pivotally mounted on said magnetic member, and said resilient means comprises a coil spring positioned in said opening under said armature.

3. The electric switching device defined in claim 1, and which includes a first electrically conductive post extending through said envelope into the interior thereof, a second electrically conductive post extending through said envelope into the interior thereof, a movable contact means mounted on said armature for selective movement thereby into contact said movable contact means.

4. The electric switching device defined in claim 3, in which said movable contact means, said second post and said U- shaped resilient member are silver plated and are bonded to one another within said evacuated envelope by atomic diffusion.

5. An electric switching device including: an armature mounted for movement between a first position and a second position; a first conductive post forming a fixed contact; a second conductive post; a movable contact mounted on said armature to be brought into electrical contact with said fixed contact when said armature moves from its first to its second position; and a U-shaped resilient strap member affixed at its respective ends to said movable contact and to said second conductive post for establishing a continuous electrical connection therebetween as said armature moves back and forth between its first and second positions.

6. The electric switching device of claim 5, in which said movable contact and said fixed contact and said resilient strap member are silver plated, and said resilient strap member is bonded to said movable contact and to said second conductive post by atomic diffusion.

7. The electric switching device defined in claim 5, in which said armature is pivotally mounted, and which includes a rod mounted on said armature and extending outwardly therefrom for supporting said movable contact. 

1. An electric switching device including: an envelope; a magnetic member forming an end wall for said envelope and having an opening therein; a movable magnetic armature mounted in said envelope and extending across said opening and movable toward and away from said magnetic member; resilient means in said envelope for biasing said armature to a first position displaced away from said magnetic member; a magnetic core member positioned in said opening in said magnetic member; a permanent magnet mounted adjacent said magnetic core member in axial alignment therewith on the opposite side thereof from said armature; and energizing means mounted adjacent said magnetic member and surrounding said magnetic core member for creating a magnetic field in said core member to draw said armature toward said magnetic core member and into the magnetic field of said permanent magnet to a second position so as to cause said armature to latch magnetically in said second position.
 2. The electric switching device defined in claim 1, in which said armature is pivotally mounted on said magnetic member, and said resilient means comprises a coil spring positioned in said opening under said armature.
 3. The electric switching device defined in claim 1, and which includes a first electrically conductive post extending through said envelope into the interior thereof, a second electrically conductive post extending through said envelope into the interior thereof, a movable contact means mounted on said armature for selective movement thereby into contact with said first electrically conductive post, and a U-shaped electrically conductive resilient member electrically connected to said second post and to said movable contact means for establishing electric contact between said second post and said movable contact means.
 4. The electric switching device defined in claim 3, in which said movable contact means, said second post and said U-shaped resilient member are silver plated and are bonded to one another within said evacuated envelope by atomic diffusion.
 5. An electric switching device including: an armature mounted for movement between a first position and a second position; a first conductive post forming a fixed contact; a second conductive post; a movable contact mounted on said armature to be brought into electrical contact with said fixed contact when said armature moves from its first to its second position; and a U-shaped resilient strap member affixed at its respective ends to said movable contact and to said second conductive post for establishing a continuous electrical connection therebetween as said armature moves back and forth between its first and second positions.
 6. The electric switching device of claim 5, in which said movable contact and said fixed contact and said resilient strap member are silver plated, and said resilient strap member is bonded to said movable contact and to said second conductive post by atomic diffusion.
 7. The electric switching device defined in claim 5, in which said armature is pivotally mounted, and which includes a rod mounted on said armature and extending outwardly therefrom for supporting said movable contact. 